Effects of heat on the biological activity of wild Cordyceps sinensis

摘要

Background:Current methods of extending the storage time of wild Cordyceps sinensis adversely affect the nutritive and medicinal value of the product.Thus,this study was designed to investigate the effects of heat treatment,a relatively safe storage extension method,on the biological activity of wild C.sinensis.Methods:Samples were heated to 60,80,or 100℃ for 15,30,or 60 minutes.SOD activity in wild C.sinensis before and after heating was assayed using a standard colorimetric assay.Deoxyribonuclease (DNase) activity was measured using the plasmid-nicking assay.Cordycepin content was analyzed using HPLC.Polysaccharide content was measured using the phenol sulfuric method.The Student's t-test was used for comparison.Results:After heating at 60,80,100℃ for 15,30,60 minutes,respectively,no significant reduction in DNase activity or polysaccharide dissolution was noted (P ＞.05).Interestingly,heating at 80℃ for 30 minutes led to a significant increase in the SOD activity of C.sinensis (P ＜.05).In addition,heating at 60℃ for 60 minutes or at 80℃ for 15 minutes significantly increased cordycepin dissolution (P ＜.05).Other heat treatments had no significant effects on SOD activity or cordycepin dissolution (P ＞.05).Conclusions:These results suggested that heat treatment does not adversely affect SOD or DNase activity,polysaccharide content,or cordycepin dissolution.Thus,heat treatment might be a safe processing method to extend the storage time of wild C.sinensis without compromising biological activity.